(HealthDay)—Chronic pain from childbirth is rare and biologic changes after a woman gives birth may prevent the development of pain after birth, according to two new studies.

In the first study, researchers interviewed more than 1,200 women within 36 hours of giving birth. Only 1.8 percent of the women who had pain when they delivered still had pain six months later and only 0.3 percent still had pain a year later, according to the study, which was published in the January issue of the journal Anesthesiology.

"The study suggests there may be a protecting mechanism that is active around the time of childbirth to prevent chronic pain from physical injury," Dr. James Eisenach, professor of obstetric and gynecologic anesthesia at Wake Forest Baptist Medical Center in Winston-Salem, N.C., said in a news release from the American Society of Anesthesiologists.

"In our accompanying lab study, we analyzed the sources of this natural protection in hopes we may be able to develop treatments to prevent chronic pain from happening after other types of trauma or surgery, similar to vaccines to prevent infectious diseases," said Eisenach, who is editor-in-chief of Anesthesiology.

The lab research, conducted in rats, suggested that elevated concentrations of oxytocin, the so-called "love hormone," in the brain and spinal cord after birth protected mothers against the development of chronic pain. Experts note, however, that results from animal research are not always replicated in humans.

"Oxytocin in the brain is considered important to mother-baby bonding, trust, love and social engagement," Eisenach said. "These results suggest the surge in oxytocin around childbirth may also speed recovery from the pain caused by childbirth."

In an accompanying editorial, Dr. Cynthia Wong, of Northwestern University in Chicago, pointed out that "both studies provide important new information toward understanding the development of chronic pain after childbirth."

And, Wong added, "understanding whether and how pregnancy protects against the development of post-traumatic chronic pain is not only important to women who give birth and their children, but may also provide therapeutic targets for future prevention and treatment of chronic pain in other populations."